Sharp MZ-3500 service manual SD1 System Loading & CP/M, Rom-Ipl

ROM-IPL

1.An 8KB ROM (2764 or mask ROM equivalent) is used for the ROM-IPL.

2.When the system reset signal turns from low to high state after power on, the main CPU starts to operate At this stage, the ROM-IPL is addressed.

3.The CPU starts from address OOOOIROM address 10000)

4.The main CPU sets the sub-CPU reset signal from low to high state as it goes out of its initial state via the memory mapper and the sub-CPU starts to operate. At this point, the ROM-IPL is addressed by the sub-CPU.

5.Address 0000 of the sub-CPU is ROM address (0000) The memory area above ROM address (1000) cannot be used by the sub-CPU because the mam CPU initial program has been loaded there.

2-2. SD1 (SYSTEM LOADING & CP/M)

SD1 determines which operating system ts in use. The system is loaded in the CP/M (Control Program for Micro- processors) mode.

M A IN	CPU
r r r
RAMicnu: \
F?'	\
^	>	\
	x	\

V

4

3

i

f. ft f n

MZ3500

Mam CPU logical address (during IPL operation)

Logical address of the sub-CPU

ROM physical address

OfFF 1 FFF 1 FFF

0800 1 800 1 800

1 7FF I 7FF

ROM IPL

0000 1 OOP 1 OOP

OFFF OFFF

0800 0800 07FF 07FF

0000 0000

MS1 = 0( L)

MSO=l(Hj

\

^ \

\\

\\

\\

\\

RAM sn

\ \

\\

\ \

\\ RAM SA

\\

\\

KAM«.(IH) 2000 1FFF

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